In general, a high-pressure side heat exchanger of a vehicular vapor compression refrigerant cycle is mounted at a front of a vehicle behind a bumper reinforcement. In a case that the bumper reinforcement extends from a right side to a left side of the vehicle in substantially the middle of the heat exchanger in a vertical direction, cooling air generally passes through a top portion and a lower portion of the heat exchanger. In some models, cooling air generally passes through left and right portions of the heat exchanger.
As for the vapor compression refrigerant cycle, for example, JP-A-2000-97504 (U.S. Pat. No. 6,189,334) proposes a method of improving a coefficient of performance by exchanging heat between a high-pressure refrigerant and a low-pressure refrigerant.